You start the server but met error with it.
The error message buffs you that your template has some errors in.

If you are not sure if the error is about syntax or about the
arguments passed from the controller, You could isolate the template problem from
controllers by directly setting up the return value in the template. such as:

<?python
message = “Hello, world!”
?>

In this case you’ll see the template still fail, it because the ‘<br>’ tag is not valid in
xhtml. you should use ‘<br/>’ instead.

All the templates used by the resources we exposed inherit from a
master template called master.html. If every page on your site has
common elements like headers, navigation links, and footers, then these
pieces belong in master.html. This is also the best place to insert
CSS and JavaScript that will be used by every page on your site.

Open tutorial/templates/master.html. There are some pieces of the welcome
screen you saw when you first started up the server, as well as some
advanced elements I won’t use in this tutorial.

The first element is for messages that you can show on the page after
the user has performed some action. The second element is a placeholder
for any elements that appear in the body of the template that inherits
from this one.

For example, if you were to return dict(tg_flash="Testmessage.") from
a controller, and the only element in that controller’s template <body>
is <p>Hello,world!</p>, this is what would be rendered:

Why should these lines be added to the top? More specifically, they should
be added before <metapy:replace="item[:]"/> because this is where any
child template’s stylesheets or scripts will be loaded, and those might
depend on the master template’s scripts already being loaded.

The second addition to master.html is any page layout markup. You could just going
to add links to several sections of your site on every page.

To do this, add the following code to the top of the <body> in master.html:

Recall that on the Users page, we want to print a list of users in the
database. Now that we have templates, we should add a link to each user’s
to-do lists as well. Change the contents of <body> in users.html to the
following:

If you added users to the database using the interactive shell, you should
be able to browse around to see the output of the above template code. This
should give you a good starting point for writing templates with Genshi.